En Sun, 18 Jan 2009 13:54:06 -0200, John Fabiani < XXXX@XXXXX.COM >
>> I have never worked with MySQL. I do work with others. The first part
>> looks fine. If you insert, update or delete then you need a 'commit' or
>> a 'rollback'. Preparing data for a report it is unlikely that you need
>> commit or rollback anything. After all you are only using 'select'.
Note that you have to commit/rollback a transaction *even* if you only
execute select statements - at least when using isolation levels higher
than "read uncommited".
By example, using "repeatable reads", a "select" on table A blocks any
attempt to modify the involved rows until the transaction ends. And using
"read commited", it won't see rows modified or added after the transaction